Ryan Reynolds as Deadpool.
Photograph: Twentieth Century Fox Film Corporation

Movies don’t come any more self-satisfied than Deadpool. From the air of smugness that pervades this Marvel adventure, you would think it was the first picture to break the fourth wall or feature a profane, badly behaved hero. In another sense, though, it has earned the right to be pleased with itself: it does break a small amount of new ground in the area of its hero’s sexual identity. In the comics from which the movie is adapted, Deadpool is pansexual – he makes no distinction between genders or gender identity in his choice of partners. The term “bisexual” would be too narrow for Deadpool, who has flirted with Thor, propositioned Spider-Man and wouldn’t rule out, say, unicorns. A pendulum moves in just two directions; he is more like a sexual swingball.

In popular culture, this is an area almost without precedent, so we shouldn’t be too hard on those Deadpool fans who have demanded a more precise definition from Fabian Nicieza, one of the comic’s creators. “I’ve been dogged with the DP sexuality questions for YEARS,” he tweeted. “It is a bit tiring. He is NO sex and ALL sexes. He is yours and everyone else’s.” Nicieza called him “the epitome of inclusive” and insisted: “He can be gay one minute, hetero the next, etc. ALL ARE VALID.” Much has been heard in the runup to the film’s release about its fidelity to this aspect of the character. He would, said the director, Tim Miller, be “pansexual. I want that quoted. Pansexual Deadpool.” Ryan Reynolds, who plays Deadpool, tweeted last year that the movie would receive an R-rating (15 or higher in the UK) for scenes of “graphic, expertly lit French unicorn sex”.

The truth is both less sensational and more interesting. The sole instance of interspecies intimacy in the film is confined to its animated closing credits, during which Deadpool is shown rubbing a unicorn’s horn until it ejaculates rainbows. Orthodox definitions of pansexuality exclude socially unacceptable manifestations of desire (necrophilia, paedophilia); the jury will have to be out for now on the question of whether cartoon sex with a mythical creature qualifies as bestiality. In all other respects, this is a Deadpool who meets in word but not deed the requirements of pansexuality. His libido is indiscriminate; every adult is fair game. But it might help his cause if he were shown having sex with someone other than his girlfriend, Vanessa (Morena Baccarin). It’s true that their antics are not exactly vanilla – he wears plastic vampire teeth to administer oral sex on Halloween and allows Vanessa to proceed beyond the point on his body where Kanye West would draw the line.

From the moment Deadpool asks us to speculate on whose balls he had to fondle to get his own movie (the answer is Wolverine’s, who has, we are informed, “a nice pair of smooth criminals down under”), his conversation is littered with homoerotic references. He asks a male bartender for a blowjob, but that turns out to be the name of a cocktail in which cream is the predominant ingredient. He calls a male cab driver “pretty damn cute” and lands crotch-first on an adversary’s face with the unconventional warcry: “Teabagged!” He speculates on the relationship between other superheroes (“I’m pretty sure Robin loves Batman”) and says, in response to the question of whether he has an on-switch: “It’s right next to the prostate. Or is that the on-switch?”

In the arena of outwardly straight men preoccupied with other men’s bodies, Deadpool is eclipsed only by the Jackass team. But how serious is he about his predilections? Without sending him into the arms or beds of other men, the movie leaves that point moot. In its entire 107-minute running time, it finds room for only one male-on-male kiss, and this takes the form of Deadpool giving a peck on the cheek to a man whom he has just threatened to rape.

On the evidence of the film, he seems (to adapt the infamous quote by Brett Anderson of Suede) to be a pansexual who has never had a non-heterosexual experience. Or, like Robbie Williams, maybe he wants to evoke the sassy, risque side of gayness without going the whole hog. “I am 49% homosexual and sometimes as far as 50%,” Williams said in 2013. “However, that would imply that I enjoy having a particular sort of fun, which I don’t.” Actions speak louder than words and there is nothing in the movie to prove that Deadpool would be any more willing than Williams to put his body where his mouth is and sample that particular sort of fun.

The film’s reluctance to make good on its hero’s pansexuality should not overshadow the little moments of daring, the subtle advancements, that have survived to the screen. In a medium characterised by the male gaze, it is implicitly radical to include a lingering closeup of a man’s pert behind, especially when that shot isn’t giving straight male viewers the get-out clause of replicating a woman’s point-of-view: everyone, male or female, is simply being invited to enjoy the image on its own merits.

A similar subversion of male identification occurs later in the film, during one of Deadpool’s fourth-wall-breaking bits of narration, when he addresses those audience members who have been dragged to see this superhero movie by their boyfriends. Once again, the assumption that an audience is male and heterosexual is challenged and overturned. (Compare a recent film such as The Big Short, where semi-naked women are used to make complicated subjects accessible to an audience who the director has assumed is largely male and straight.) When Deadpool speaks over the heads of men in the audience, it’s almost as delicious as that moment in The Opposite of Sex when Christina Ricci warns female viewers that if their boyfriends are squirming over the gay scenes in the movie, they may be protesting too much.

While it’s a pity that Deadpool, both character and film, don’t venture beyond heterosexual sex, it still has the makings of an intriguing piece of queer superhero cinema, a genre so small that its exponents don’t even make it into double figures. The X-Men movies (with which the action of Deadpool overlaps briefly) expertly deploy the idea of the mutant as a metaphor for difference and queerness. In X-Men 2, there is even a version of the traditional coming-out scene, only in this case the character, Bobby (Shawn Ashmore), is confessing to being a mutant. “We still love you,” his mother says, then asks: “Have you tried not being a mutant?”

But you would have to go all the way back to Tank Girl, the 1995 movie of Jamie Hewlett and Alan Martin’s comic book series, to find a genuine precursor to Deadpool’s pansexuality. Obvious shortcomings (animated inserts stand in for scenes that were never shot) can’t diminish the refreshing strangeness of a film that fails to recognise standard movie-hero codes of behaviour. Tank Girl (Lori Petty) begins the picture with a boyfriend – it’s his murder that is the catalyst for her revenge mission. But, in truth, he is forgotten before too long and soon she is pretending to be lovers with Jet Girl (Naomi Watts) while falling in with the Rippers, a crowd of kangaroo-human mutants who have more than a touch of the beatnik about them. A scene showing Tank Girl lying in bed with the sweetest Ripper, Booga (Jeff Kober), who is stroking her head with his ear, is both playful and revolutionary. No wonder the movie was a flop when it asked audiences to root for a hero who couldn’t even confine her affections to her own species.

A person without defined sexual parameters is dangerous and unstable in society’s eyes because they can’t easily be monetised. Tick the box that says “gay” or “straight”, “single” or “married”, and you have placed yourself in a category as a customer. Fickle consumers may as well not be consumers at all for all the economic consistency they represent. They like cornflakes, extreme sports and the Twilight novels this week. Next week, it could be scrambled eggs, philately and bondage. Loyalty cards are wasted on them. Heroes such as Deadpool and Tank Girl, with their roving tastes, are the fictional equivalent, which explains why there are so few of them. Most cinema audiences cherish reassurances; unpredictability can be discomfiting, especially the sexual sort.

So, while there is an argument that the version of James Bond found in Ian Fleming’s original novels can be read as sexually ambiguous, this element has been alluded to just once in a Bond movie. It occurs in the brief scene in Skyfall when Silva (Javier Bardem) flirts with Bond (Daniel Craig), only for the latter to allude to past sexual experiences with men. (“What makes you think it’s my first time?” he purrs.) Asked about that electrifying moment, Craig was both enigmatic and pleasingly matter-of-fact. “I don’t see the world in sexual divisions,” he said. Spoken like a true pansexual.

The best representations of non-heterosexual characters are usually those where no special effort has been made to accommodate sexuality. Think of the character who turns out to be gay at the end of the stop-motion animation ParaNorman: nothing is altered there but our own assumptions. Or the private investigator played by Val Kilmer in Kiss Kiss Bang Bang. Kilmer had liked the screenplay, but believed it would be deepened if there were an extra frisson between his character and the thief-turned-actor played by Robert Downey Jr. “I said, ‘We gotta get a little colour in here. We gotta juice it up a little. I think I should be gay. I think I should kiss Robert Downey in the middle of the film. Maybe even earlier. Several times.’” (Kilmer also observed knowingly that “maybe this wasn’t my first gay role. Maybe that was Top Gun.”)

Only one character in movie history, however, has truly lived the pansexual dream without compromise: Bugs Bunny. No one else has followed his whims with such single-mindedness. No other movie hero has flitted back and forth across gender lines with a nonchalance that renders those divisions obsolete, and few have looked so fetching in lipstick. He dressed in female clothing more than 40 times between 1939 and 1996 (most famously in The Wabbit Who Came to Supper, in which he wore lingerie, and with blonde pigtails as Brünnhilde in What’s Opera, Doc?). And he was never shy of planting a juicy smacker on the lips of Yosemite Sam or Elmer Fudd. Come to that, Bugs was razing the fourth wall long before Deadpool got his first box of Lego. The new movie makes quite a song-and-dance about its uninhibited hero. To anyone brought up on the pansexual adventures of Bugs Bunny, though, it’s in danger of looking like a walk down memory lane.